1. Field of the Invention
The invention is directed to vehicle borne radar systems, and more particularly to such systems which utilize wayside transponders to communicate with and provide information to the vehicle.
2. Description of Related Art
There is a continuing need to improve the safety of highway vehicles to prevent such vehicles from impacting with moving and stationary objects. Concurrently, there is a need to safely increase the density of vehicles traveling the world's roadways. These seemingly opposing goals can be achieved by providing a means for each vehicle to monitor the distance, speed and direction of other vehicles traveling on the same roadway. A number of systems are presently known which allow such monitoring to be accomplished relatively inexpensively and accurately.
In addition to increasing the density and safety of our roadways, there is a further desire to improve the flow of information between vehicles and information gathering services, such as traffic information services and highway police, to allow traffic to move smoothly around areas of congestion and to provide a means by which an operator of a vehicle can be alerted to dangerous or otherwise interesting conditions ahead. Currently, information is transmitted to operators of vehicles by a number of wireless transmissions. For example, many radio stations which broadcast over frequencies that can be received by the AM/FM radio that is installed in most vehicles today, communicate at least some information relating to traffic conditions during peak travel times (i.e., "rush hours"). While such information is helpful to some people, this information is generally directed to a very large and diverse audience. Therefore, specific information and recommendations are rarely possible.
Local low power narrow casts have also been used to communication information to operators of vehicles in connection with resorts, airports, and other local areas that attract large numbers of vehicles. These transmissions are transmitted on frequencies that can be received by common AM/FM radios, but are transmitted at very low power levels to limit the range of the transmission, and thus the size of the audience. While such local transmissions may be useful in some instances, they are not interactive (i.e., they cannot receive information from vehicle, and respond to such received information).
The present invention combines the notion of a radar system which can monitor other vehicles that share the roadway, and thus improve the safety of the roadway, and the notion of an interactive message system that can receive interrogations from a vehicle borne system and respond to those interrogations to inform the operator of a vehicle of roadway and traffic conditions.